What actually happens when you type a URL into the browser and press Enter?

The interview-grade version, in order: 1. DNS — browser asks 'what IP is this domain?' Checks its cache, then the OS, then a resolver, which walks root → TLD → authoritative nameservers. 2. TCP — browser opens a connection to that IP on port 443 (three-way handshake: SYN, SYN-ACK, ACK). 3. TLS — certificates are exchanged and verified, encryption keys negotiated. The padlock. 4. HTTP — browser sends `GET /`, the server (often via load balancer → app server → database) builds and returns HTML. 5. Rendering — browser parses HTML, discovers CSS/JS/images, fetches those in parallel, builds the DOM + CSSOM, runs JS, paints pixels. Senior-level bonus: mention caching at every layer — DNS cache, CDN, browser cache — and that HTTP/2 multiplexes those parallel fetches over one connection.